It may be possible, if the gap is predictable and the same from one pistol to the next. Probably depends on how close a gap you want nominally?

I modelled the pistol from dimensions provided to me by IMADMAN. Dimension I did not have, I assumed for the sake of appearance. So, if I am provided the distance from the base of the air tank to the shroud front face, I can model what you seek, with perhaps a 1 or 2 mm gap. The gap in my model is 6.35 mm or .25". Everything looks larger, when you zoom in on it.
I have the adapter supplied by Kelly @ Kraz Kool, so the moderator snugs up flush with the front of the shroud. The distance between the front of the air cylinder and the front edge of the shroud is 11.5mm. The front sight height is 3.5mm, so may have to allow clearance for it so it doesn't interfere with screwing it onto the adapter.
 
I know what makes the impulse so good. Could easily do a DFL insert to mimic the impulse. By easily, I mean after the other project I have started are completed, or written off as failures.
That would be very interesting to try. Can you tell us what you think makes the impulse so good in this application?
 
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That would be very interesting to try. Can you tell us what you think makes the impulse so good in this application?

The slant angle on those cones is around 20 degrees, included angle. This works well to scoop up air very well, regardless of whether the air has a high bulk pressure but is moving forwards comparatively slowly; or if the air is moving fast because it has already expanded, and thus has less bulk pressure left.

The second factor is the spacing between baffles. They are far enough apart for the air flow to follow the back of the cones, rather than taking a shortcut from one baffle bore to the next. Visualize a troop of monkeys swinging swiftly between closely spaced monkey bars; compared to bars that are spaced too far apart for the motion to propagate; forcing the monkey to drop off and walk some distance on the ground, before reaching the next monkey bar.

More hints, starting with the last sentence of the second paragraph:
https://www.airgunnation.com/threads/choosing-the-correct-size-moderator.1296366/post-1566050
 
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The slant angle on those cones is around 20 degrees, included angle. This works well to scoop up air very well, regardless of whether the air has a high bulk pressure but is moving forwards comparatively slowly; or if the air is moving fast because it has already expanded, and thus has less bulk pressure left.

The second factor is the spacing between baffles. They are far enough apart for the air flow to follow the back of the cones, rather than taking a shortcut from one baffle bore to the next. Visualize a troop of monkeys swinging swiftly between closely spaced monkey bars; compared to bars that are spaced too far apart for the motion to propagate; forcing the monkey to drop off and walk some distance on the ground, before reaching the next monkey bar.

More hints, starting with the last sentence of the second paragraph:
https://www.airgunnation.com/threads/choosing-the-correct-size-moderator.1296366/post-1566050
Many thanks for the hints and explanations. I’d love to learn more but I guess we should respect the fact that this is a general GK1 thread. It might be useful to start a separate GK1 moderator thread, given the context of need, diversity in form and application and the fabulous progress that you, TTTM and others are making (and validating)
 
I just had an email from my supplier indicating that the Huben mod adapters were messed up by over anodizing. They offered (and I accepted) a version in which the anodizing was removed from the threads. I already have one from Zach so I’m considering modding the new one to vent back to a tube surrounding the barrel, to implement a working shroud. Is that worth doing (subscriber, TTTM etc) or would it be a better use of my time to improve my recipe for squirrel vindaloo?
 
Since I suggested it (and it was endorsed by Matthias and several thumbsups) I figured I better do it. So here it is:


I added a basic summary and my own recommendation of the Impulse Air. It would be great if others, particularly our wise and wonderful design and printing gurus, could provide a summary of where they are at. If it doesn’t take off and turns into a dud thread, I can delete it. The ball is in your court, fellow GK1 enthusiasts!
 
I just had an email from my supplier indicating that the Huben mod adapters were messed up by over anodizing. They offered (and I accepted) a version in which the anodizing was removed from the threads. I already have one from Zach so I’m considering modding the new one to vent back to a tube surrounding the barrel, to implement a working shroud. Is that worth doing (subscriber, TTTM etc) or would it be a better use of my time to improve my recipe for squirrel vindaloo?
There is not much volume between barrel and shroud; and the bottom of the shroud is open; so I think the rear venting system would be louder to the shooter's ears. IMADMAN has proposed a fully functional shroud for the Huben pistol. I told him; one thing at a time :)
 
I was looking everywhere for a dummy machined fill prope lol.
like this?
PXL_20230917_004148235.jpg

View attachment huben_fill_plug.zip
 
There is not much volume between barrel and shroud; and the bottom of the shroud is open; so I think the rear venting system would be louder to the shooter's ears. IMADMAN has proposed a fully functional shroud for the Huben pistol. I told him; one thing at a time :)
Unfortunately my scale crapped out so I’m unable able to weigh the shroud. There is a lot of weight and mass there for just being basically a cover with a front sight and 11mm dovetail. Ideally a redesigned cover with intergraded sound suppression, front sight and a built in picatinny/ weaver style base is what’s in my head.
 
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@subscriber I printed your 8 1/2" moderator. It sounds a little quieter than the 5" version. Technically it should be about 2 dB quieter. 3 dB is suppose to be the minimum detectable change in sound level detectable by the human ear and is about 1/2 the power.

I am on a trip now and will not be home for another couple of weeks. Will run some tests when I get back.

Thanks for the design.

Jim K.

Heben4.jpg